Vegetation changes with climate change in the Grandes Rousses mountain range
Data files
Apr 12, 2024 version files 146.66 KB
Abstract
Questions: We assessed interactions between climate change, bedrock types and snow cover duration on the trajectories of taxonomic and functional composition of subalpine plant communities. We predict (i) an increase in species richness on siliceous bedrock due to a reduced competition and a decrease in richness on calcareous bedrock due to increasing drought stress, (ii) decreasing snow cover duration should induce a higher shrub encroachment in hollows as compared to ridges (iii) increasing growing season temperature should induce taller sizes and more conservative growth traits, in particular in hollows.
Location: Subalpine belt of the Grandes Rousses mountain range, south western Alps (France).
Methods: 189 vegetation plots were sampled in 1997 and 2017-2018. The duration of snow cover was assessed during two years in 1995-1997 and five functional traits were measured on 108 species in 2021. We performed multivariate analyses, quantified community weighted-means (CWM) of traits and used ANOVAs to detect responses to local-scale factors and changes in snow cover, temperature and precipitation since 1997 according to a nearby meteorological station.
Results: Overall, taxonomic composition weakly changed and changes were more dependent on the position of communities along the snow cover duration gradient than on their bedrock type. The abundance of drought-tolerant species increased at the border of hollows and there was, over all communities, a slight increase in the abundance of dwarf shrubs and tall herbaceous species, a strong decrease in short herbaceous species and, thus, an overall decrease in species richness. There were important overall changes in CWM of size traits, in particular leaf area which increased the most in hollows irrespective of bedrock types.
Conclusion: In this subalpine site the effects of decreasing snow cover duration overwhelmed the effects of bedrocks, which may explain the overall increase in competitive species and decrease in species richness.
README: Vegetation changes with climate change in the Grandes Rousses mountain range
Principal investigator (or person responsible for collecting the data):
Richard Michalet, University of Bordeaux, France, richard.michalet@u-bordeaux.fr
Date of data collection:
1997, 2017, 2018
Information about geographic location of data collection:
Isère department, France.
The file, created in 2024, includes 2 sheets :
1. Vegetation composition : Vegetation plots data (Fig. 2 & 3).
2. Plant traits : CWM of plant traits (Fig. 4 & 5).
There are no restrictions on the data.
Description of methods for data collection or generation:
Vegetation composition was sampled using quadrat sampling (Michalet et al. 2002, Arctic, Antarctic & Alpine Research).
Plant traits measurements and CWM calculation are done following Michalet et al. (2023, Ecology).
Description of methods used for data processing:
We used CA for vegetation composition and PCA for plant traits, both followed by ANOVAs.
Variable list, units of measurement:
Sheet 1 (vegetation composition):
N° (information): plot number.
Year (effect variable): year of sampling.
All other columns (species names): Species counts.
Sheet 2 (plant traits):
Species (information): species names.
Height: extended height (cm).
Width: lateral extension (cm).
LDMC: Leaf Dry Mass content (percentage).
SLA: Specific Leaf Area (cm2.g-1).
LA: Leaf Area (cm2).
Definitions for codes or symbols used to record missing data: n/a.
Methods
189 vegetation quadrats were done in 1997 and 2018.
We measured plant traits and calculated CWM of traits at the two years of sampling.